She crossed the finish line — and then continued on to the great beyond.

An celebrated ocotogenarian runner who loved the sport so much that she proclaimed “I want to die running” suffered a deadly injury when she stumbled during Sunday’s New York City Marathon.

Joy Johnson, 86, of San Jose, Calif., died Monday from complications of blunt trauma to her head and blood-thinning drug therapy for a heart ailment, according to the Medical Examiner’s Office.

Johnson’s death was ruled an accident, spokeswoman Grace Brugess said.

Johnson’s younger sister, Faith Anderson, said Johnson — who was running her 25th consecutive New York City Marathon — told her that she tripped and fell around Mile 20 of the five-borough foot tour.

That stretch features a dreaded uphill approach to the Willis Avenue Bridge, where many runners hit “the Wall” and lose steam.

Another competitor helped Johnson to her feet and she resumed running, with unofficial results showing that she crossed the finish line after 7 hours, 51 minutes, 41 seconds, making her the oldest woman to complete Sunday’s race.

“She did what she wanted,” said Anderson, 83, of Young America, Minn.

“She said: If I can die running I’ll die happy.”

A spokesman for marathon organizer New York Road Runners said Johnson went to the medical tent after finishing the 26.2-mile course and was “alert and in good spirits.”

“When evaluated by our medical team she was strongly advised to allow our Emergency Medical Services team to take her to the hospital for further evaluation, but Joy declined,” said Chris Weiller of NYRR.

“Our deepest condolences go out to Joy’s family and friends. She was an inspiration to us all.”

Johnson’s death came shortly after she and her sister made their annual post-race pilgrimage to Rockefeller Center to see “Today” show host Al Roker, who greeted Johnson warmly.

“He says to her, ‘What happened to you? You have some bandages,’” Anderson recalled.

“She said, ‘I wasn’t watching where I was running.’ She said, ‘I’m fine, it just looks awful.”

But when they returned to their room at the Roosevelt Hotel, Johnson lay down on her bed and lapsed into unconsciousness, Anderson said.

Hotel security workers and EMTs were unable to revive her, and Johnson was taken to Bellevue Hospital where doctors pronounced her brain dead and Anderson decided to have her taken off life-support machines, she said.

Anderson said her widowed sister began running after retiring as a physical-education teacher, and had completed more than 70 marathons across the country.

“I always said, if we started at the same time I’d get there two weeks later,” Anderson said.

A devout Lutheran who ran every day but Sunday so she could attend church, Johnson sang hymns to herself and “thought happy thoughts” to pass the time while running, Anderson said,

Daughter Diana Boydston, 54, said of her mom: “She was always a happy runner — and besides her faith and family, this was something she loved the most.”